Fixed phpstan issues

Author: ddebowczyk

packages/doctools/src/Docgen/FrontmatterStripper.php

@@ -78,7 +78,7 @@ public function stripContent(string $content): string
         }
 
         // Find closing ---
-        $withoutLeading = preg_replace('/\A\s*/', '', $content);
+        $withoutLeading = preg_replace('/\A\s*/', '', $content) ?? $content;
         $endPos = strpos($withoutLeading, "\n---", 3);
         if ($endPos === false) {
             return $content;

packages/doctools/src/Quality/Services/DriftDetector.php

@@ -218,7 +218,11 @@ private function loadTierMap(string $repoRoot): array
             return [];
         }
 
-        $json = json_decode(file_get_contents($path), true);
+        $contents = file_get_contents($path);
+        if ($contents === false) {
+            return [];
+        }
+        $json = json_decode($contents, true);
         if (!is_array($json) || !isset($json['packages'])) {
             return [];
         }

packages/events/src/Dispatchers/EventDispatcher.php

@@ -29,7 +29,7 @@ class EventDispatcher implements CanHandleEvents
     /** @var array<string, string[]> Cached class hierarchy per event class */
     private static array $typeCache = [];
 
-    /** @var callable[]|null Pre-sorted tap listeners, null = needs rebuild */
+    /** @var array<callable(object): void>|null Pre-sorted tap listeners, null = needs rebuild */
     private ?array $sortedTaps = null;
 
     public function __construct(
@@ -194,7 +194,7 @@ private function classListeners(object $event): iterable
     /**
      * Returns pre-sorted tap listener callables (cached between addListener calls).
      *
-     * @return callable[]
+     * @return array<callable(object): void>
      */
     private function resolvedTapListeners(): array
     {